Recent pneumatic tires are required to have various kinds of enhanced performance, and their tread patterns are contrived to enhance the performance. Heavy duty tires are provided with tread patterns that enhance traction performance.
For example, heavy duty pneumatic tires with both enhanced traction properties when running on bad roads at the terminal stage of wear and wet performance during high-speed running are known (see Japanese Unexamined Patent Application Publication No. H09-136514A). This heavy duty pneumatic tire is a pneumatic tire having at least one circumferential groove extending in the circumferential direction, and a plurality of lateral grooves arranged at intervals in the circumferential direction on both sides of the circumferential groove, and linking with the circumferential groove; wherein
(1) the circumferential groove extends in the circumferential direction in a tread central region that corresponds to 50% of the tread width;
(2) the depth of the circumferential groove is 5% of the tread width or greater; and
(3) the depth of at least lateral grooves disposed in both side sections of the tread among the lateral grooves is 109% of the depth of the circumferential groove or greater.
Accordingly, both the traction properties when running on bad roads and wet performance during high-speed running can be enhanced.
With the heavy duty pneumatic tire as described above, although the traction properties in the terminal stage of wear can be enhanced, the cut resistance can be easily reduced by the occurrence of defects or the like in blocks on the tread portion, due to off-road running.